Charmed-quark model for narrow resonances

An isospin suppression is used as a possible explanation of the narrow width of the 3.1-GeV resonance in a model with three charmed quarks. This follows from an analogy with $\rho -\omega$ mixing and the $\omega \to 2\pi$ decay. The decays and widths of radial excitations of the 3.1-GeV resonance are discussed. The weak couplings of the model predict different decays for charmed particles than other models with charm; in particular, $K$ mesons are not always found in the decays. An experimental test which clearly distinguishes this model from other models is given.